Corrosion-inhibiting mineral oil compositions



United States CGRROSION-INHIBITING MINERAL OIL COMPOSITIONS 9 Claims. (Cl. 252-34} This invention relates to mineral oil compositions containing certain acidic condensation products of maleic acid and maleic anhydride and dimers of dienoic and trienoic fatty acids, or certain oil-soluble derivatives of said condensation products. More particularly, the invention relates to mineral oil compositions of improved corrosion inhibiting characteristics, ,having incorporated therein the aforesaid acidic condensation products or the oilsoluble amine salt, amide and ester derivatives of said acidic condensation products.

As is well-known in the art, uncompounded mineral oils are often deficient in one or more respects for the particular use to which they are put. For example, a high resistance to rust or corrosion is important in the case of fuels or lubricants which contact metal surfaces in the presence of water. Failure to provide sufficient resistance to rust or corrosion by a particular mineral oil may result in extensive wear or damage to costly, finely machined moving parts and/or damage to storage and transport facilities and the like. To overcome this and other deficiencies of uncompounded mineral oils, various agents known as addition agents, additives or improvement agents are incorporated in many mineral oils. Fuels or lubricants for internal combustion engines and for gas or steam turbines are examples of materials which desirably may have incorporated therein additives or improvement agents which impart corrosion inhibiting properties thereto.

We have found that the corrosion and/or rust inhibiting characteristics of mineral oils can be markedly improved by the incorporation therein of small amounts of the herein-described acidic condensation products and certain oil-soluble amine salts, amides and esters thereof. The class of acidic condensation products, or adducts, whose use is embraced by the invention includes the acidic condensation products of (a) maleic acid or maleic anhydride and (b) dimeric acids derived from unsaturated fatty acids that contain 6 to 22 carbon atoms and 2 to 3 ethylenic linkages per molecule. The oilsoluble organic derivatives of the foregoing acidic condensation products Whose use is included by the invention are members selected from the group consisting of (a) amine salts, and amides of the foregoing acidic condensation products and aliphatic monoamines containing 8 to 22 carbon atoms per molecule, and (b) esters of monohydric alcohols containing 8 to 22 carbon atoms per molecule and said acidic condensation products.

The particular manner in which the herein disclosed reaction products of this invention function to inhibit corrosion has not been definitely established, and for atent ice this reason the invention is not limited to any particular theory of operation. Presumably, however, the reaction products of this invention function by formation of a protective, adsorbed film of oriented molecules upon metallic surfaces contacted thereby.

The acidic condensation products whose use is included by this invention can be prepared as such in any suitable manner. For example, they can be prepared using the procedure customarily resorted to in making the well-known Clocker adducts from ordinary nonconjugated unsaturated fatty acids and maleic acid or maleic anhydride. According to one preferred procedure, the unsaturated acidic condensation products that form the nuclei of the oil-soluble amine salts, amides and esters of this invention can be formed by condensing maleic acid, or preferably the corresponding anhydride, and a dimer of a diethenoic or a triethenoic fatty acid in approximately theoretical reacting proportions at an elevated temperature. The theoretical reacting proportions are determined on the basis of the number of olefinic linkages in the dimer acid. For example, one mol of a dimer acid containing two ethylenic linkages per molecule, e.g., dimerized linoleic acid, can be condensed with one to two mols of maleic anhydride, and one mol of the dimer of linolenic acid can be condensed with one to three mols of maleic anhydride. Acidic condensation products prepared from substantially equimolar proportions of maleic acid and dimerized unsaturated fatty acid are considered especially useful for the purposes of this invention. Elevated temperatures of about 250 to about 500 F. can be used in carrying out the condensation reaction, but some deviation from these temperatures is permissible provided the temperature employed is at least sufficient to permit the reaction to take place, and not so great as to cause substantial decomposition of the reactants or the acidic condensation product. Temperatures of about 300 to 400 F. are especially advantageous from the standpoint of a suitabie rate of reaction and of minimizing side reactions. For example, excellent results have been obtained at temperatures of about 350 F. The reaction can usually be carried substantially to completion in a period of about 30 minutes to about 3 hours, depending upon the specific reactants and reaction temperature employed. Little advantage will be obtained by the use of longer reaction periods.

The dimeric acids and the maleic acid or anhydride or anhydrides disclosed herein condense with one another intermediately in the carbon chain of the respective reactants in such a manner that the carboxylic or dicarboxylic anhydride portion of the respective reactants is not altered. The product of the above-described condensation reaction is therefore a polybasic condensation product. While the exact mechanism of the condensation of dimerized unsaturated fatty acids and maleic acid or anhydride has not been fully established, it appears likely that during the condensation reaction, the maleic acid or anhydride becomes saturated by transfer of a hydrogen atom, perhaps from a carbon atom involved in a double bond in the dimer acid, but more probably from a carbon atom adjacent to one involved in a double bond, to either the alpha or beta carbon atom of the a es-mes former, and by attachment of the remaining monovalent dimer acid radical to the alpha or beta carbon atom that did not add the hydrogen atom. The product of such an addition is a dimer acid-substituted succinic acid or anhydride. For example, a condensation product of one mol of maleic anhydride and one mol of dimerized linoleic acid might have any of the following structural formulas:

Oil-soluble amine salt, amide and ester organic derivatives of the acidic adducts disclosed herein can be obtainedin any suitable manner. According to a preferred procedure, the oil-soluble aminesalt, amide and ester derivatives of the acidic condensation products disclosed herein are obtained by reaction of at least" one member of the group consisting of aliphatic monohydric alcohols containing Sto 22'carbon atoms per molecule and aliphatic'monoamines containing 8 to 22 carbon atoms per molecule with one of the above-described acidic condensation products of a dimeric' acid andmaleic acid or anhydride in a mole ratio ranging from 'one mol of the alcohol or amine per mol of acidic condensation product, to a number of molsof alcoholor amine that is equal to the number of carboxyl groups in one molecule of acidic condensation product, per ml .of acidic condensation product. For example, one to four mols of lauryl amine or lauryl alcohol can be reacted With'one mol of the acidic condensation product of one mol of maleic anhydride and one mol of dimerized linoleic acid. Where more than one carboxyl group of the acidic condensation product of a dimeric acid and maleic acid is to be neutralized, it is not necessary that they be neutralized with'the same member; for example, partly neutral and neutral mixed ester-amine'salt and ester-amide derivatives of the class'disclosed*arespecifically included by the invention.

The reaction conditions utilizedin obtaining-the part- 1y. .or incompletely neutral and neutral amine salt, amide and ester derivatives of theacidic condensation products disclosed herein are those conventionally used for amidation, esterification, and amine salt formation, and COD.- sequently, these conditions form no part of the invention. Thus, esterification can be effected at temperatures of about250 to about 500 F..with temperaturesof about 300 to 400 F. being preferred. The esterification reaction is normally substantially complete after about 30 minutes to 3 hours, depending on the particular reactants and the reaction temperature. Esterifica- .tion can be facilitated by the use of conventional esterification catalysts. For example, sulfuric acid and p-toluene sulfonic acid can be used as catalysts. The alcohols disclosed herein appear to react preferentially with the carboxyl groups of the acidic condensation products of this invention, since esterification will take place, to the extent possible, with the elimination of water, in a number of mols corresponding to the number of mols of alcohol that are reacted.

Amidation of the acidic condensation products disclosed herein with an amine, using a 1:1 mol ratio, can be effected over a Wide range of temperatures, temperatures of about 180 F. to about 500 F. being satisfactory when the acidic condensation product is in the form of an acidic anhydride. Higher temperatures, e.g., about 300 to 450 F., preferably at least about 350 F should be used when the acidic condensation product is not in the form of an anhydride, or where the latter is being reacted with more than one mol of amine to form a poly-amidated product. The amidation is usually substantially complete in about 30 minutes to 3 hours, depending upon the particular reactants and the reaction conditions. The amines disclosed herein appear to react preferentially with the acid anhydride group of the condensation products of this invention. Thus, for example, two mols of cocoamine will react with a 1:1 condensation product of dilinoleic acid and maleic-anhydride at a temperature of 350? F. and above to form a diamide, with the elimination ofonly one mol of water.

In the case of mixed ester-amide derivatives, his not necessary to carry out the esterification and amidation independently, and both reactions "can be'effected simultaneously. Nor is it necessary that *the esterification and/or amidation reaction be carried out independently from the condensation reaction involving themaleio'acid and the dimerized ethylenic fatty acid. These reactions can sometimes be advantageously effected simultaneously in the same reaction vessel at the same'condition's. In addition, the esters and amides of the dimer acid and/or the maleic acid or anhydride can be'formed prior to the condensation reaction, if desired.

The acidic condensation products of dimerized di and tri-ethanoic fatty acids and maleic acid,-and the incompletely amidated and/or esterified derivatives thereof readily form amine saltsby simple addition at moderately elevated temperatures, but the speed of the reaction can usually be accelerated appreciably by the use of heat of about 180 to about 325 F. Temperatures above about 325 F. are to be avoided, since such temperatures are conducive to amide formation rather than salt formation. Where an acidic anhydride group is present in the acidic condensation product the temperatures specified tend to promote the formation of amides rather than amine salts.

In all of the amine salt, amide and ester derivatives or the condensation products discussed above, the total number of mols of amide and/or alcohol used in the amidation, esterification and/or salt formation reactions with the acidic condensation product of the dimerized ethenoic fatty acid and the maleic acid or anhydride, will be the same or less than the product of the number of mols of the'acidic condensation product and the numberof carboxyl groups per molecule of'said acidic condensation products. For example, in the case'of a partly neutral derivative of an-acidic condensation productformed by the partial neutralization of one mol-of the potentially tetracarboxylic 71:1 mol ratio condensation product of maleic acid or anhydrideand'dimerized linoleic'acid with a C aliphatic monoamine, e.g., lauryl amine,-and/or a identical.

if desired, the amine salts, amides and esters of the neutral acidic condensation products disclosed herein can be prepared by effecting the esterification, amidation, and/or salt-forming reactions in mineral oil dispersion. This expedient is often of advantage in that better control of the reaction is achieved. Moreover, the resulting amine salt, amide or ester derivatives of the acidic condensation products of this invention are in the form of mineral oil concentrates that can be added as such to the mineral oil compositions of this invention. Alternatively, the herein disclosed acidic condensation products and the amine salt, amide and ester derivatives thereof can be prepared as such and subsequently diluted with mineral oil or other solvent, to form additive concentrates.

Alpha, beta ethylenic dicarboxylic acids or anhydrides that are suitable for condensation with the dimerized diand tri-ethenoic fatty acids'disclosed herein are maleic acid and maleic anhydride. Except where otherwise indicated, the term acid and the like, as used in connection with maleic acid and acid condensation products thereof with dimers of diand tri-ethenoic fatty acids, is intended to include the corresponding acid anhydrides.

Dimerized diand tri-ethenoic fatty acids capable of forming acidic condensation products with maleic acid or anhydride are prepared from monomeric di or tri-olefinic fatty acids having the generic formula C H COOH, where n is an integer of 5 to 21 and x is 3 or 5. As will be evident, such monomeric acids contain 6 to 22 carbon atoms and will contain 2 or 3 ethylenic linkages per mole- .cule as the ratio of carbon to hydrogen increases, i.e., as x increases from 3 to 5. Dimerized acids corresponding to the addition products of the foregoing acids can therefore be defined by the generic formula:

where n is an integer of to 42 and x is an even integer of 6 to 10. These dimeric acids are therefore dibasic, i.e., dicarboxylic, acids having 12 to 44 carbon atoms per molecule. The method of preparing dimeric acids is conventional and forms no part of this invention.

Dimers derived from monomeric dienoic acids that have 18 carbon atoms, especially those having conjugated ole finic linkages, are preferred for reasons of economy, ease of dimerization of the monomers and the general excellence of the amine salt, amide and ester derivatives of the acidic condensation products prepared from such dimers. A specific example of a preferred dimer acid is dimerized linoleic acid, i.e., dilinoleic acid. Examples of other dimerized acids that form suitable acidic condensation products with maleic acid for the purposes of this invention are dimers of dienoic acids such as sorbic (hexadienoic), humoceric (nondecadienoic) and eicosenic (eicosadienoic) acids, and dimers of trienoic acid such as linolenic and eleostearic (octadecatrienoic) acids.

It is not necessary that both of the unsaturated fatty acid molecules of the bimolecular addition product be Dimers of mixed composition such as those obtained by dimerized mixed dienoic, mixed trienoic or mixed dienoic and triencic acids such as can be derived from certain naturally occurring drying oils, e.g., linseed oil and soybean oil, are satisfactory.

Alcohols that form suitable esters with the acidic conden'sation products of dimerized diand tri-ethenoic fatty acids and maleic acid, for the purposes of this invention, are aliphatic monohydric alcohols containing at least 8 and preferably 8 to 22 carbon atoms per molecule,

whether saturated or unsaturated. Aliphatic monohydric alcohols containing at least 12 and preferably 12 to 18 carbon atoms per molecule are especially suitable for the purposes of this invention. An example of a preferred aliphatic monohydric alcohol is lauryl alcohol. Other alcohols, the use of which is included by the invention, are n-octyl alcohol, capryl alcohol, Z-ethylhexyl alcohol, stearyl alcohol, myristyl alcohol, cetyl alcohol, oleyl alcohol and C and higher Oxo-process branched chain alcohols.

Amines capable of forming suitable amides and/or amine salts with the acidic condensation products of this invention, or the partly esterified derivatives thereof, are aliphatic monoamines containing at least 8 and preferably 8 to 22 carbon atoms per molecule. The use of primary, secondary and tertiary "amines, having straight or branched carbon chains, is included by the invention. Primary amines containing at least 12 and preferably 12 to 18 carbon atoms per molecule are preferred, A specific example of a preferred amine is lauryl amine. Examples of other amines, the use of which is included by the present invention, are n-octyl amine, t-octyl amine, myristyl amine, n-hexadecyl amine, t-dodecyl amine, t-hexadecyl amine, stearyl amine, oleyl amine and n-docosyl amine.

It is not necessary that individual amines or alcohols be employed, and commercial mixtures, for example, such as can be derived from naturally occurring fats and oils, can be used. In such instances the amine or alcohol mixtures will contain primary straight chain aliphatic monofunctional amines or alcohols containing 8 to 22 carbon atoms. Cocoamine and Lorol, derived from coconut oil fatty acids, are respective examples of suitable commercial amine and alcohol mixtures. These materials are respectively mixtures of C alkyl monoamines and monohydric alcohols containing even-numbers of carbon atoms, the principal components of which are lauryl amine and lauryl alcohol, respectively.

Specific examples of preferred acidic condensation products and oil-soluble organic derivatives thereof included by this invention are the 1:1 mol ratio condensation product of maleic anhydride and the dimer of linoleic acid, the dilauryl ester of the 1:1 mol ratio condensation product of maleic anhydride and the dimer of linoleic acid, the mono-lauryl amide of the 1:1 mol ratio condensation product of maleic anhydride and the dimer of linoleic acid, the mono-, di-, and tri-lauryl amine salts of the mono-lauryl amide of the 1:1 mol ratio condensation product of maleic anhydride and the dimer of linoleic acid, the mono-cocoamide of the monoand (ii-lauryl esters of the 1:1 mol ratio condensation prodnet of maleic anhydride and dimerized linoleic acid, and the pentalauryl ester of the 1:2 mol ratio condensation product of maleic anhydride and dimerized linoleic acid.

Specific examples of other partly neutralized acidic adducts included by the invention are the trilauryl ester, the dilauryl amide, the trilauryl amide, and the mixed monolauryl amide-monolauryl ester of the 1:1 mol ratio condensation product of maleic acid or anhydride and the dimer of linoleic acid. Other acidic condensation products and oil-soluble derivatives included by the invention are the 1:2 mol ratio condensation products of maleic anhydride with dimers of linoleic, linolenic, and eleostearic acids, the 1:1 mol ratio condensation products of the foregoing alpha, beta ethylen-ic dicarboxylic acids and anhydrides. with dimers of linolenic and eleostearic acids, and the mono-, diand tri-octyl, octadecyl and octadecenyl amides, amine salts and mono-, diand tri-octyl, octadecyl, octadecenyl and docosyl esters of these acidic condensation products.

The following specific examples are illustrative of the mode of preparation of various acidic condensation products and, neutral or partly neutral, oil-soluble organic derivatives thereof, whose use is included by this invention.

.was the mono-lauryl amide.

Hui: EXAMPLE I man's Accordin?g .to .this example an oil-solul'a l"ev ester of arsenic condensation product according to this inventionwas preparedby admixing one mole of dimerized lino eic acid and onelrriol ofinaleic anhydride'in a reaction ,vessel and heating the mixture for about we ihour'sat about ,3 Q x z i i i condensation product fdlmerizle'dlino leic ac da I anhydride. The reaction mixture was thefif'coole'dfto about 190 E, and, two molsot lau r yl. alcohol were added. This the ted to ab outfli'a gfi" and maintainfedat ahove th s temperament a 1.1 40 minutes, approx tely two rnol s of wat'erhbeiiig trapped oflf. The ditn linoleic acid employed in this example was a commercialproduct (Emery, 955 Dimer Acid, Emery Industries, nc, CincinnatLOhio), consisting mostly of the dimer of 9,l.1-octadecadiei1oic acid:

onatonz l onoin-oniomompoohh Canaries-on 'ngonmooon oH= H The commercial dimer acid has the following typical inspections:

Physical state ';l Viscous liquid Molecular weight (appr x.) L 6,00 Iodine value 80-95 -Acid value j 189 -192 Saponification value 185- 195 Unsaponifiable 2.0% max. Color, Gardner -a 12 max. Neutralization equivalent 290-310 Dimer content, percent (approx) 85 Trimer content, percent (approx) l2 Monomer content, percent (approx) 3 Refractive index at:25, C. 1.4919 Specific gravity at 155 C./l5.5 C. 0.95 Flash point, F. 530 Fire point, F. 600

Viscosity at 100 C., centistokcs Q. 100

EXAMPLE 1! Another acidic adduct according to this invention was prepared by admixing one mole of the dirner-ized linoleic acid-referred to in Example I with one mol of maleic anhydride and one mol of cocoamine and heating the mixture for two hours, at a temperature of about 325 F.

.The cocoamine used in this example was a commercial product (Armour & Company, Chicago, Illinois) having a combining Weight of about 210 and consisted mostly of lauryl amine together with compounds homologous thereto in the C 4 (even-numbered) range. The product of this reaction consisted essentially of the mixed monococoan1ides of the 1:1 mol ratio condensation T he product of dilinoleicyacid and maleic anhydride. predominant component of the mixed monococoamides The product of the react-ion was a brownish solid.

EXAMPLE HI pared similarly as in Example II, except that two mols were required). washed and heated to 285 F.. to dry. The product, a

of cocoaminewere employed. Iheiuroduct pfi misreaction wasalso a brownish solid and consisted essentially of the mono-cocoamine addition salt of mam cocoamide of the 1:1 mol ratio condensation product ofdimerized linoleic acid andmaleic anhydride The Prin ipal: omp t. of h mi ed p o c .Was...t e m no-lauryl am n dition sa t o the moncrl y amide of the above-indicated condensation product.

EXAMPLE IV Another amine. saltamide derivative was prepared as in Example II, except that three mols of cocoamine were employed 'in the reaction. The product ofithis reaction was also a brownish solid consisting essentially of the di-cocoamine addition salt of. the monococamide in the 1:1 mol ratio condensation product of dimerized linoleic acid and maleic anhydride. The principal component of the mixed salts was the di-lauryl amine salt of the monolauryl amide of said conde'nsation product.

EXAMPLE V Still another amine salt-amide derivative of an acidic condensation product according. to this invention was prepared by a procedure substantially identical to that describedin Example II, except that four mols of cocoarnine were utilized in thereaction. The productof this reactionwas likewise a-bro'wnish 'so1id,'ahd it consisted mostly .of the tri-cocoamine addition salt of 'the monococoamide. of the 1:1 mol ratio condensation product of dimerized linoleic acid and Ymaleic anhydride. The principal component ofthe 'mixed'product was the tri-lauryl amine salt of the mono-lauryl amide of the, aforesaid condensation product.

EXAMPLE VI allowed to drop to 200 F., and enough cocoamine was added to bring the pH up to 7 (approximately 1.7 mols The resulting product was then watertan solid, was the mixed monoand dicocoamides of the 1:2 mol ratio condensation product of dimerized linoleic acidand maleic anhydride.

EXAMPLE VII Another ester derivative of an acidic condensation product disclosed herein was prepared by reacting one mol-of the dimerized linoleic acid described in Example 'I with-two mols of maleic anhydride at a temperature of 350? F. for about two hours, to form a 1:2 mol ratio wacidic condensation product.- The reaction mixture was then cooled to about F. and five mols of lauryl alcohol were added thereto. The te'mperature of the mixture was then raised to 340 F. and maintained at or above this point with refluxing, until about three mols of Water had been trapped off. The product of this reaction Was a semisolid material having a grayish color, and it consisted essentially of the pentalauryl ester of the 1:2 mol ratio condensation product of dimerized linoleic acid and mal'eic anhydride.

' EXAMPLE vnr A mixed ester-amide derivative of an acidic condensation product according to this invention was prepared by :reacting one mol of the ,dime'rized linoleic acidof Example I with are molof maleic anhy'cliide at about 350 F. for about two hours, to form a 1:1 mol ratio acidic condensation product. This condensation product was then cooled to 190 F. and two mols of lauryl alcohol were added. The resulting mixture was then heated to 350 F. under reflux and maintained at this point or 1 EXAMPLE IX According to this example 0.7 mol of each of (a) maleic anhydride, (b) the dilinoleic acid described in Example I and (c) lauryl alcohol, were reacted at 340-500 F. for two hours to form the monolauryl ester of the 1:1

mol ratio condensation product of dimerized linoleic acid and maleic anhydride. The resulting reaction product was then cooled below 200 F. and 0.7 mol of cocoamine was added, and the mixture was heated to a temperature of about 250 F. for between two and three hours. Theproduct of this reaction, a light brown solid, was the monococoamide of the monolauryl ester of the 1:1 mol ratio condensation product of dimerized linoleic acid and maleic anhydride.

The foregoing examples are illustrative only, and the acidic condensation products of maleic acid or anhydride and other dimerized diand tri-ethenoic (3 fatty acids, disclosed herein, and oil-soluble esters, amine salts and amides of said acidic condensation products and C aliphatic monohydric alcohols and monoamines can be prepared in substantially identical fashion.

The acidic condensation products disclosed herein are useful as corrosion inhibitors and as intermediates in the preparation of the oil-soluble amides, amine salts and ester derivatives disclosed herein. Because of their relatively lower oil-solubility, it may be necessary to employ dispersants or solubilizing agents, such as alkali metal sulfonates, butyl Cellosolve (ethylene glycol monobutyl ether), butyl Carbitol (diethyleneglycol butyl ether), or the like, to obtain bright oil compositions containing the acidic condensation products. The class of amine salt, amide and ester derivatives indicated possesses superior mineral lubricating oil-solubility characteristics as compared with the acidic condensation products themselves, and for this reason the former find especial utility. By way of illustrating the lubricating oil-solubility characteristics of the acidic condensation products and their derivatives, 0.05 percent by weight of the 1:1 mol ratio acidic condensation product of dimerized linoleic acid and maleic anhydride failed to dissolve completely in the mineral lubricating oil described in Example X below, as evidenced by the hazy appearance of the oil sample. In contrast, the same amount of each of the derivatives of this acidic condensation product described in Examples I to V, inclusive, and in Examples VIII and IX dissolved completely, as evidenced by the bright or transparent appearance of the oil samples.

The neutral and partly neutral amine salt, amide and ester derivatives disclosed herein can be incorporated in the desired mineral oil vehicle in any suitable manner. For example, they can be admixed with the desired mineral oil either as such or in the form of concentrated solutions or dispersions. In a preferred embodiment the amine salts, amides and esters of this invention are employed in a mineral lubricating oil, for example, a turbine lubricating oil. Examples of other mineral oil compositions which can be benefited by the incorporation therein of the amine salts, amides and esters of this invention are kerosene, gasoline, diesel fuel, furnace oil, motor oil and lubricating greases.

The acidic condensation products of this invention and the amine salts, amides, and esters disclosed herein are useful when incorporated in mineral oil compositions in minor proportions, suflicient to confer rust and corrosion inhibiting properties thereupon. For example, the acidic condensation products and the amine salts, esters and amides of this invention are useful when incorporated in mineral oil compositions in amounts of about 0.01 to 1.0 percent, the optimum amount varying with the character of the mineral oil composition and the specific nature of the reaction products. For example, good results are obtained when the acidic condensation products, and especially when the amine salts, amides and esters of this invention are employed in mineral oils in amounts of about 0.01 percent by weight of the composition. Ex-

cellent results are obtained when the latter materials are incorporated in mineral oils in amounts of 0.025 to 0.1 percent by weight of the composition. However, as

pointed out above, up to about 1.0 percent by weight of the composition of the reaction products of this invention can be used, if desired.

The invention includes mineral oil compositions where the mineral oil vehicle is not employed as a fuel or lubricarit but merely as a solvent vehicle. In such instances the compositions may contain substantially in excess of 1 percent by weight of the composition of the amine salt, amide and ester derivatives of this invention. Examples of solvents that can be used in such compositions are light naphtha, mineral spirits and the like.

The specific embodiments set forth in the following example illustrate suitable mineral oil compositions included by the invention.

EXAMPLE X To each of nine separate samples of a highly refined, highly paraflinic turbine lubricating oil, a typical sample of which had an API gravity of 31.7", a Saybolt Universal viscosity of 336 seconds/70 F., 150.5 seconds/ F., 85.2 seconds/ F. and 43.8 seconds/210 F., a viscosity index of 110, a pour point of +5 R, an ASTM Union color of less than one and a Conradson carbon residue of 0.01 percent, was added 0.05 percent by weight of one of the products prepared in specific Examples I to IX. The turbine oil base employed in the various embodiments of this example contained 1.25 percent of 2,6-t-butyl,4-methylphenol as an oxidation inhibitor, and 0.0001 percent by weight of Dow-Corning Silicone Fluid 200 (dimethyl silicone fluid) as a foam inhibitor. Neither of these materials has any apparent effect upon the corrosion-inhibiting characteristics of the base oil stock or of the acidic condensation products, amine salts, amides or esters of this invention.

The corrosion-inhibiting characteristics of the mineral oil compositions of this invention have been demonstrated by subjecting mineral oil compositions containing amine salts, amides and esters included within the scope of this invention to the standard procedure of the ASTM turbine oil corrosion test ASTM D665-52T, Procedure A. This test is described in ASTM Standard on Petroleum Products and Lubricants for November 1952. Briefly, this test involves immersion of a previously polished, standard steel test rod in a 300 ml. sample of the test oil, to which there is added 30 ml. of distilled water, and maintaining the test rod in contact with the agitated mixture of oil and water for 24 hours. At the end of the test period the test specimen is observed for rusting. The improvement in corrosion-inhibiting properties obtained by the use of the reaction products of this invention was determined by comparison of the rusting obtained with a blank sample of the base turbine oil described in Example ,X with the results obtained with each of the-inhibited test oil samples described in Exam- 'RunNo V V .1516 x. ,The results a the as are gre'sena in the following table:

were

- u as beincorporat'ed in mineral oil solvents, such a li h which are p yed neither as a fuel noias a Table H J an, ..4', .5 .6 smwe r Make-up, percent by Wt.:

Base Oil 3 s i Dilauryl Ester of 1:1 Condensation Product of Dimerized Linoleic Acid and Maleic Anhydride (Example I Product).

ioo

Mono-lauryl Amide of- 121 Condensation Product of Dimerizcd Linoleic Acid and Maleic Anhydride (Example II Product) Mono-lauryl Amine Salt of Mono-lauryl Amide of the 1:1

Condensation Product of Dimerized Linolcic Acid and *Maleic Anhydride (ExampleIII Product) Di-lauryl Amine, Saltot Mono-lauryl Amide of the 1:1 Condensation Product of Dimerized Linoleic Acid and Maleic Anhydride (Example IV Product) Tri-laury1 Amine Salt of Mono-lauryl Amide ofthe 1:1

Condensation Product of Dimerized Linoleic Acid and 'Maleic Anhydride (Example-V Product) Mixed Monoand Di-lauryl Amides of the 1:2 Condensation Product of Dimerized Linoleic Acid and Maleic Y Anhydride (Example VI Product).

Pentalauryl Ester of the 1:2 Condensation Product of Di- Inerived Linoleic Acid andMaleic Anhydnde (Example VII Product) Mono-lauryl Amide of Dilauryl Ester'of 1:1 Condensation Product of Dimerived Linoleic Acid and Maleie Anhydride (Example VIIIProduct).

Mono-lauryl Amide of Monolauryl Ester of 1:1 Condensation Product of Dimerired Linoleic Acid and Maleic Anhydride (Example IX Product) Inspection: ASTM D 665-52 T, Procedure A, 24 Hours Busting. severe l trace 0 0 0 0 i 0 0 0 Trace equals 0 rust to l rust spot, one mm. diameter. Comparison of the results obtained in test runs 2 to 10, inclusive, with those obtained in test run 1 demonstrates the beneficial results obtained with the additives included by tbisinvention. Similar improvement is obtainable by substitution in the foregoing embodiments in the same or equivalent proportions, or in other proportions disclosed herein, of other'herein disclosed amine salts, amides and esters of other C aliphatic monoamines and/or other Ci aliphatic monohydric alcohols and the, condensation products of other dir'ncri'z'ed dietben'oic or triethenoic C acids and malcic acid or anhydride. 7 v Q The importance of the presence of the "dimerized dior tri-cthenoic acid residues in thefultima'te rust inhibiting products disclosed herein is demonstrated by com- ,parison of the results set forth in Table A with those set foith in Table B below. Base Oil. referred to was the same as that used in the test oils describedin Example X, and the reaction product'slindicated were obtained by a procedure substantially In the following table the the} same as that disclosed for the additives of this invention.

Table B Run No 1 2 Make-up: Percent by Wt.: 7

Monolauryl Amide of. Monolaur Ester of 1:1

Condensation Product of Linoleic Acid and 'Maleic Anhydride; ,0. DilaurylEster of 1:1 Condensation Product f 1 Oleic Acid and Maleic Anhydi'ide 0.05

Inspection: .ASIM D 665-52 T, Procedure A, 24

Hours Busting, percent 5 5 Comparison of the results obtained with the test oils in runs 2 to 10, inclusive, of Table A with the te'st'oils diinerizcd ethenoic acid residue.

In addition to the specific embodiments disclosed above the acidic condensation products and the amine salts,

amides and esters disclosed herein also can be employed in "gasoline, furnace oil, diesel 'oil, slushifig'oils, motor oils and other oils, The use or these sdeiiiyesm mineral lubricants is. considered particularly advantageous. As

has been gih cated the acidic condensation ,products the smile salts, atnids and esters described herein can lubricant; In such instances the compositions find use in the coating art, wherein a metallic article subject to rust or corrosion can be brushed, dipped, or sprayed with the composition comprising the solvent and the additive. Subsequent evaporation of the solvent deposits an adlierent, corrosion resisting coating of the additive upon the metal article. The acidic condensation products and the amine salts, amides and esters of this invention can also be used as corrosion inhibiting additives in paints, varnishes, automobile undcrcoatings and the like. In the do use ofthe acidic condensation products and the amine salts, amides and esters of this invention in various coating compositions, it can be advantageous to employ the formerin substantially greater concentrations than are normally utilized in fuels and lubricants.

While the foregoing description has in the main been directed to reaction products wherein not all of the carboxylic groups have' been reacted, it will be understood that many obvious derivatives of such partly neutralized acidic condensation products can be'prepared and are ineluded by the invention. For example, there can be prepared olefin oxide derivatives, e;g., ethylene oxide and propylene, oxide derivatives, derivatives of low molecular weight amines, i.e., low molecular Weight amine salts and amides, e.g., methyl amine, mono-, di-, and triethanol amine, alkali and alkaline earth metal salts and ammonium salts, and esters'of 'low molecular weight alcohols, e.g., methyl, ethyhpropyl and butyl alcohols.

It is to be understood that the improved mineral oil compositions of this invention can be additionally bene- 0 fitted by the incorporation therein of other known improverncnt agents adapted to confer other desirable properties upon the composition. For example, there can be added antioxidants, viscosity index improvers, thickeners, pour point improvement agents, bearing corrosion inhibitors, detergents, dispersants, soaps, dyes, ex

treme pressure agents and the like.

Resort can be had to such modifications of the inventionas do not depart from the spirit of the invention or the scope of the appended claims.

This is a divisionof our copending application Se'rial .No. 503,006, 'filed April 21, 1955, now Patent No. 72,902,499 W .z i A mineral oil composition comprisingja;major proportion of a mineral oil having incorporated therein a minor amount sutficient to impart corrosion inhibiting properties to the composition of a member selected from the group consisting of (I) acidic condensation products of (a) a dimeric acid derived from an ethenoic fatty acid that contains 2 to 3 ethylenic linkages and 6 to 22 carbon atoms per molecule, and (b) a member selected from the group consisting of maleic acid and maleic anhydride, Where the mole ratio of (a) to (b) is 1:1 to 1:2 when the dimeric acid is derived from a dienoic acid and 1:1 to 1:3 when the dimeric acid is derived from a trienoic acid, and (II) organic derivatives of said acidic condensation products selected from the group consisting of amine salts and amides of aliphatic monoamines that contain 8 to 22 carbon atoms per molecule and whose substituents are hydrocarbon radicals, and esters of unsubstituted aliphatic monohydric alcohols that contain 8 to 22 carbon atoms per molecule. a

2. A mineral oil composition comprising a major proportion of a mineral oil having incorporated therein a minor amount, sufficient to impart corrosion inhibiting properties to the composition, an organic derivative of an acidic condensation product of (a) a dimeric acid derived from an ethenoic fatty acid that contains 2 to 3 ethylenic linkages and 6 to 22 carbon atoms per molecule, and (b) a member selected from the group consisting of maleic acid and maleic anhydride, where the mole ratio of (a) to (b) is 1:1 to 1:2 when the dimeric acid is derived from a dienoic acid and 1:1 to 1:3 when the dimeric acid is derived from a trienoic acid, said organic derivatives of said acidic condensation product being selected from the group consisting of amine salts and amides of aliphatic monoamines that contain 8 to 22 carbon atoms per molecule and whose substituents are hydrocarbon radicals, and esters of unsubstituted aliphatic monohydric alcohols that contain 8 to 22 carbon atoms per molecule.

3. The mineral oil composition of claim 2 wherein said minor amount is about 0.01 to about 1.0 percent by weight of the composition.

4. The mineral oil composition of claim 2 wherein said 14 minor amount is about 0.025 to about 0.1 percent by weight of the composition.

5. A mineral oil composition comprising a major amount of a mineral lubricating oil and a minor amount, sufiicient to impart corrosion inhibiting properties to the composition, of a dilauryl ester of the 1:1 mol ratio condensation product of dimerized linoleic acid and maleic anhydride.

6. A mineral oil composition comprising a major amount of a mineral lubricating oil and a minor amount, sufi'icient to impart corrosion inhibiting properties to the composition, of a mono-lauryl amide of the 1:1 mol ratio condensation product of dimerized linoleic acid and maleic anhydride.

7. A mineral oil composition comprising a major amount of a mineral lubricating oil and a minor amount, suflicient to impart corrosion inhibiting properties to the composition, of a lauryl amine salt of a mono-lauryl amide of the 1:1 mol ratio condensation product of dimerized linoleic acid and maleic anhydride.

8. A mineral oil composition comprising a major amount of a mineral lubricating oil and a minor amount, sufiicient to impart corrosion inhibiting properties to the composition, of a pentalauryl ester of the 1:2 mol ratio condensation product of dimerized linoleic acid and maleic anhydride.

9. A mineral oil composition comprising a major amount of a mineral lubricating oil and a minor amount, sufiicient to impart corrosion inhibiting properties to the composition, of a mono-lauryl amide of a lauryl ester of the 1:1 mol ratio condensation product of dimerized linoleic acid and maleic anhydride.

References Cited in the file of this patent UNITED STATES PATENTS 2,630,441 Dazzi Mar. 3, 1953 2,718,503 Rocchini Sept. 20, 1955 2,833,715 Lemmon et al. May 6, 1958 2,902,499 Gottshall et a1. Sept. 1, 1959 'UNITED STATES PATENT OFFICE W CETIFICATION OF CORRECTION Patent No. 2,975, 133 March 14, 1961 Ralph I. Gottshall et a1.

It is hereby certified'that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 4 line 61, for "amide" read amine Signed and sealed this 25th day of July 1961.

(SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD i Attesting Officer Commissioner of Patents UNITED STATES PATENT OFFICE CERTIFICATION OF CORRECTION Patent No. 2,975,133 March 14, 1961 Ralph 1. Gotts-hall et a1.

It is hereby certified'that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below Column 4, line 61 for "amide" read amine Signed and sealed this 25th day of July 1961.

(SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer 7 Commissioner of Patents 

1. A MINERAL OIL COMPOSITION COMPRISING A MAJOR PROPORTION OF A MINERAL OIL HAVING INCORPORATED THEREIN A MINOR AMOUNT SUFFICIENT TO IMPART CORROSION INHIBITING PROPERTIES TO THE COMPOSITION OF A MEMBER SELECTED FROM THE GROUP CONSISTING OF (I) ACIDIC CONDENSATION PRODUCTS OF (A) A DIMERIC ACID DERIVED FROM AN ETHENOIC FATTY ACID THAT CONTAINS 2 TO 3 ETHYLENIC LINKAGES AND 6 TO 22 CARBON ATOMS PER MOLECULE, AND (B) A MEMBER SELECTED FROM THE GROUP CONSISTING OF MALEIC ACID AND MALEIC ANHYDRIDE, WHERE THE MOLE RATION OF (A) TO (B) IS 1:1 TO 1:2 WHEN THE DIMERIC ACID IS DERIVED FROM A DIENOIC ACID AND 1:1 TO 1:3 WHEN THE DIMERIC ACID IS DERIVED FROM A TRIENOIC ACID, AND (II) ORGANIC DERIVATIVES OF SAID ACIDIC CONDENSATION PRODUCTS SELECTED FROM THE GROUP CONSISTING OF AMINE SALTS AND AMIDES OF ALIPHATIC MONOAMINES THAT CONTAIN 8 TO 22 CARBON ATOMS PER MOLECULE AND WHOSE SUBSTITUENTS ARE HYDROCARBON RADICALS, AND ESTERS OF UNSUBSTITUTED ALIPHATIC MONOHYDRIC ALCOHOLS THAT CONTAIN 8 TO 22 CARBON ATOMS PER MOLECULE. 